1. Field of Invention
The present invention relates to a work transfer lock system and method for engaging and disengaging work devices while locking and unlocking relatively moveable platforms such as a rotating superstructure of a crane.
2. Description of the Background Art
The conventional art of FIG. 5 illustrates a cab 3 which is mounted on a superstructure bearing base plate 16. Superstructure bearing base plate 16 is rotatably mounted on a carrier bearing base plate 18. The superstructure bearing base plate 16 is rotatable about a rotation axis AA. The superstructure bearing base plate 16 can rotate either clockwise or counter clockwise as indicated by directional arrow R. When the cab 3 and the superstructure bearing base plate 16 are not rotated, an operator can steer a carrier chassis 19 with a steering wheel 6. The carrier chassis 19 includes a steering box 14 which is operatively linked to the steering wheel 6 when an operator desires to steer the chassis 19 from the cab 3.
The hardware between the steering wheel 6 and steering box 14 is disconnectable so that superstructure bearing base plate 16 can rotate relative to the carrier bearing base plate 18 and the carrier chassis 19. To prevent rotation of the cab 3 and the superstructure bearing base plate 16 relative to the carrier bearing base plate 18 and the carrier chassis 19, a lock pin 4 is employed to fasten the superstructure bearing base plate 16 to carrier bearing base plate 18. In an engaged position, the lock pin 4 restricts movement of the cab 3 and the superstructure bearing base plate 16 when an operator desires to steer the carrier chassis 19.
The hardware between the steering wheel 6 and steering box 14 includes a mechanical steering link 8 which includes a first shaft 10 and a second shaft 12. The first shaft 10 is connected to the wheel 6 while the second shaft 12 is connected to the steering box 14. This conventional design requires at least two separate actions of the operator to engage or disengage steering control from the cab 3: (1) an operator must exit the cab 3 in order to engage or disengage the mechanical steering link 8; and (2) the operator must locate the lock pin 4 and disengage or engage lock pin 4 depending upon the desired operation.
The conventional design allows an operator to disengage the lock pin 4 from the carrier bearing base plate 18 to permit rotation of the cab 3 and superstructure bearing base plate 16 while the first shaft 10 and second shaft 12 are connected. Such a situation where the mechanical steering link 8 operatively connects the steering box 14 to the steering wheel 6 while the lock pin 4 is disengaged from the carrier bearing base plate 18 can result in substantial or permanent damage to the mechanical steering link 8.
Accordingly, a need in the art exists for a work transfer lock system and method thereof for engaging and transferring steering control from a actuator on a first platform to a second steering device on a second platform while limiting movement between the first platform and the second platform. Further, a need in the art exists for a work transfer lock system and method thereof which substantially reduces the amount of manual labor required in engaging and disengaging a steering link between a steering device on a superstructure and a steering device on a chassis or carrier.